Screwless electric connector



Sept. 29, 1959 H. PERGANDE SCREWLESS ELECTRIC CONNECTOR Filed Nov. 28, 1955 United States Patent 2,906,989 SCREWLESS ELECTRIC CONNECTOR Hermann Pergande, Berlin-Wilmersdorf, Germany, ,assignor to-Erich Hofmann, Dusseldorf-Stadium,- Germany Application November 28, 1955, Serial No. 549,480

Claims priority, application Germany November 29, 1954 '3 Claims. (Cl. 339-105) My invention relates to pressure connectors for electric 'wires.

There are known connectors of this type' wherein the wire is fastened, without the use of screw bolts or nuts, by the pressure action of springs, cones, balls, eccentrics, wedges or the like clamping means.

These knovm connectors leave much to be desired. Some of them are too large or too complicated in design or use. Others are too expensive to manufacture, do not reliably clamp the wire, or can accommodate only one wire per clamping place.

It is an object of my invention to obviate these shortcomings and to provide a space-saving pressure clamp which is cheap and simple to manufacture and use, and which permits clamping two wires per clamping place, including wires of difierent diameters.

To this end, and in accordance with my invention, I provide a pressure connector with a metal plate of rhombic shape, truncated on opposite ends, whose four marginal portions are curved upwardly from the plate surface substantially along a semicircle so as to define a shallow sleeve space which decreases in width from the middle of the plate toward both truncated ends. This plate structure is surrounded by an insulated enclosure and accommodates two movable clamping pieces of fiat circular shape, the height of the sleeve space being substantially equal to the height of the flat clamping pieces. Each clamping piece has a cross section larger than the smallest cross section of the sleeve space, and both pieces are urged by a spring toward the respective narrow openings of the sleeve space.

These and more specific features of the invention are apparent from the embodiment illustrated by way of example on the drawing in which- 7 Fig. 1 shows a perspective view of the metal-plate structure with its semicircularly curved edge portions,

Fig. 2 shows a partly sectional top view of the entire pressure connector,

Fig. 3 is an end view of the connector, and

Fig. 4 is a cross section of one of the clamping pieces of the connector.

According to the invention, a rhombic metal connector shell 1, truncated at the upper and lower ends as shown in Fig. 1, has four edge portions 2 which curve upwardly away from the plate surface and have a substantially semicircular cross section. The connector shell structure 1, namely the plate together with its edge portions, thus defines a sleeve space of substantially oval cross section. Disposed in this oval space are two clamping pieces 3 which are formed as circular discs and are both movable along the axis of the connector shell structure. The cross section across the diameter of each clamping piece is larger than the narrowest cross section across the width of the oval sleeve space. A leaf spring 4 of wavy shape is disposed between the two clamping pieces 3 and urges each toward the narrowest place of the oval sleeve space. The peripheral edge of each clamping piece 3 has the same semicircular shape3a. as the curved edge poring body 5 whose interior shape is similar to thatof-the shell. As a result, a closed hollow spaceofoval shape is formed whose two opposite, oval openings are lined with metal. Into each of these oval openings a wire can be inserted between the clamping piece 3 and the semicircular portion of the shell structure. The wires thus insertable may have different diameters. By virtue of the rhombic shape of the connector, the wire is firmly clamped in position by the spring-biased clamping piece, the clamping force being the stronger the more pull is exerted upon the wire. Nevertheless, the wires can be readily removed if desired, it being then only necessary to push the clamping piece back into the hollow space of the connector.

The clamping pieces and the leaf spring have a slightly smaller height than that of the oval hollow space within the connector. The ends of the leaf spring 4 are preferably bent at a right angle to the axis of the connector. Instead of forming the clamping pieces 3 as circular discs, these pieces may also be formed of rings having the same outer diameter as the above-described discs.

I claim:

1. A pressure connector for electric wires, comprising a shell of metal having a truncated and tapering shape and forming substantially oval cross sections throughout the length of said shell, each oval cross section having a corresponding width and depth, said shell forming an elongated oval opening at at least one truncated end thereof suitable for insertion of two wires of different diameters to be clamped, said shell and said cross sections thereof defining an interior hollow space tapering toward said opening, a flat circular clamping disc movable in said space, said disc having a diameter larger than the smallest width of said cross sections and a thickness corresponding to the smallest depth of said cross sections, aid disc protruding partially out from said opening when inactive, and spring means in said space for urging said disc toward said opening.

2. A pressure connector for electric wires, comprising a metal shell truncated at its end and having two semicircular edge portions tapering toward a truncated end of said shell to define a shallow trapezoidal sleeve space therein forming substantially oval cross sectionsthroughout the length of said shell, said sleeve space decreasing in Width toward said truncated end to provide each of said oval cross sections with a respective width and constant depth throughout, said shell forming at said truncated end thereof an elongated oval opening suitable for insertion of two wires of different diameters to be clamped, a flat circular clamping disc movable in said sleeve space and having a diameter larger than the smallest width of said cross sections, and a thickness corresponding to said constant depth of said cross sections, said disc having a rounded peripheral edge engaging and substantially mating with said semi-circular shape of said edge portions, said disc protruding partially out from said opening when inactive, and spring means disposed in said space and engaging said disc for urging it toward said opening.

3. A pressure connector for electric wires, comprising a shell formed from a metal plate having a rhombic shape, truncated at opposite ends thereof and having two semicircular edge portions curving upwardly from the plate surface and tapering toward said respective truncated ends so as to define a shallow sleeve space having oval cross sections throughout the length of said shell, each cross section being of mutually equal depth and of various widths corresponding to the taper of said shell, said shell forming at said truncated ends thereof, openings coinciding with cross sections of smallest width, an insulating enclosure surrounding said shell, two flat clamping discs of circular shape located in said space,,each of said discs having a diameter larger than the two, smallest widths of said cross sections and a depth substantially equal to said mutually equal depth of said cross sections, and spring means located between said two discs and urging them respectively toward said cross sections of smallest width.

References Cited in the file of this patent UNITED STATES PATENTS Bainbridge Mar. 12, 1889 Kyle June 14, 1938 Hofrnann Nov. 13, 1956 FOREIGN PATENTS Great Britain Oct. 17, 1951 Germany June 26, 1942 

